Properties of the Number 21609

Twenty-One Thousand Six Hundred Nine

Basics

Value: 21608 → 21609 → 21610

Parity: odd

Prime: No

Previous Prime: 21601

Next Prime: 21611

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 7 ⁴

Divisors: 1, 3, 7, 9, 21, 49, 63, 147, 343, 441

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101010001101001

Octal: 52151

Duodecimal: 10609

Hexadecimal: 5469

Square: 466948881

Square Root: 147

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Numbers n such that A048767(n) = n. A48768

Primal codes of finite idempotent functions on positive integers. A109298

Primal codes of finite permutations on positive integers. A109297

Perfect powers of nonsquarefree numbers k that are not squareful. A386762

Numbers of the form 3ⁱ*7^j with i, j >= 0. A3594

a(n) = (6·n+3)². A16946

Number of 2 X n 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically. A207069

Numbers whose prime factors are 3 and 7. A33850

Numbers with prime factorization p²*q⁴. A189988

T(n,k) = Number of (n+2) X (k+2) 0..1 arrays with each row divisible by 5 and each column divisible by 7, read as a binary number with top and left being the most significant bits. A262759